There's only a limited number of documented events that can actually kill a Japanese office worker.
1) Overwork. This is the most common because for the purpose of narrative it can simply "happen" where ever the location is most convenient.
2) Traffic accident. The triggering event is most often the act of rescuing a child or an animal and not just "spontaneous vehicle." Although it could take the elements of exhaustion from point 1 and make use of that as a triggering event instead (wandering out into the road when you shouldn't).
3) Conbini robbery prevention. End result is being stabbed and bleeding out, although I'll admit in my reading history this option has only had minimal presence.
For all we know, this guy is simply just related to
Tsutomu Yamaguchi.